Functional Characterization of a Dendrobium officinale Geraniol Synthase DoGES1 Involved in Floral Scent Formation.

Conghui Zhao,Jaime A Teixeira Da Silva,Haobin Wang,Mingze Zhang,Jun Duan,Danqi Zeng,Chunmei He,Zhenming Yu,Can Si

doi:10.3390/ijms21197005

Abstract

Floral scent is a key ornamental trait that determines the quality and commercial value of orchids. Geraniol, an important volatile monoterpene in orchids that attracts pollinators, is also involved in responses to stresses but the geraniol synthase (GES) responsible for its synthesis in the medicinal orchid Dendrobium officinale has not yet been identified. In this study, three potential geraniol synthases were mined from the D. officinale genome. DoGES1, which was localized in chloroplasts, was characterized as a geraniol synthase. DoGES1 was highly expressed in flowers, especially in petals. DoGES1 transcript levels were high in the budding stage of D. officinale flowers at 11:00 a.m. DoGES1 catalyzed geraniol in vitro, and transient expression of DoGES1 in Nicotiana benthamiana leaves resulted in the accumulation of geraniol in vivo. These findings on DoGES1 advance our understanding of geraniol biosynthesis in orchids, and lay the basis for genetic modification of floral scent in D. officinale or in other ornamental orchids.

Highlights

Plants emit an astonishing number of volatile metabolites during growth and development, and these have various roles, some with biological effects, that are considered beneficial to plants and humans [1]
It contributed to the regulation and production of geraniol biosynthesis
DoGES1 was located in chloroplast, and could utilize GPP to singly produce geraniol in vitro

Summary

Introduction

Plants emit an astonishing number of volatile metabolites during growth and development, and these have various roles, some with biological effects, that are considered beneficial to plants and humans [1]. Floral volatiles have a dual function, to attract pollinators, and in defense against pests, herbivores, and pathogens [2,3,4]. Economically important floricultural crops, possess an abundance of floral volatile terpenes. Monoterpenes, especially geraniol, linalool, and their oxygenated derivatives, are predominant components of floral scents [4,5]. Geraniol is an acyclic monoterpene alcohol released from several ornamental plants, such as citronella, geranium, herbs, roses, and orchids (Phalaenopsis bellina and Dendrobium officinale) [5,6,7,8], and is extensively used in fragrance and cosmetics industries because of its pleasant rose-like scent.

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Conclusion